For a method of manufacturing a semiconductor device including a silicon carbide substrate, a technique for forming an ohmic electrode on the silicon carbide substrate has been developed.
For example, according to Japanese Patent Laying-Open No. 7-99169 (PTL 1), by forming an Ni—Si alloy layer or a stack of Si and Ni on an SiC base (a silicon carbide substrate), NiSi2 (33 atomic % of Ni and 67 atomic % of Si) can be formed without supply of Si from the SiC base and an electrode in ohmic contact with the SiC base is obtained. In addition, according to this publication, when Ni is not more than 33% in an atomic ratio, Si is excessive and conductivity is impaired, and when Ni is not less than 67%, excessive Ni is present at an interface between NiSi2 and SiC and the interface becomes discontinuous. Further, according to this publication, since Si is not supplied from SiC, such a phenomenon that excessive C diffuses into Ni and it is precipitated as graphite at a surface of an electrode does not occur.